AbbVie has secured an exclusive right to buy Kestrel Therapeutics for up to $1.45 billion, with the biotech required to hit unspecified development and regulatory milestones before AbbVie pulls the trigger.
This is an option structure. AbbVie funds the KST-6051 program now; the full buyout comes if milestones are met. The companies didn’t disclose what those milestones are, which makes the $1.45 billion headline hard to evaluate.
KRAS has become a competitive corner of oncology. AstraZeneca inked a $2 billion deal with Jacobio for KRAS inhibitors in December 2025, and many big pharmas have been building positions in the space. AbbVie’s option ceiling is lower, but it’s buying into Phase 1 — KST-6051 just started dosing Tuesday, the same day Kestrel announced the deal.
What does AbbVie actually get? KST-6051, an oral pan-KRAS inhibitor for solid tumors, is the lead asset. About 20% of all malignancies carry a KRAS mutation, making this one of oncology’s largest addressable populations. Amgen’s Lumakras, the first approved KRAS drug, targeted a specific mutation and had limited patient impact. Kestrel’s pan-KRAS approach is a broader bet, and AbbVie VP Eleni Lagkadinou said the partnership will pursue mutations that prior drugs didn’t reach.
No close date disclosed. The real question isn’t the $1.45 billion ceiling; it’s how many milestones AbbVie needs Kestrel to clear before it commits.
— Diana Kowalski